全文获取类型
收费全文 | 20401篇 |
免费 | 1752篇 |
国内免费 | 585篇 |
专业分类
耳鼻咽喉 | 782篇 |
儿科学 | 183篇 |
妇产科学 | 168篇 |
基础医学 | 2183篇 |
口腔科学 | 1188篇 |
临床医学 | 1849篇 |
内科学 | 1058篇 |
皮肤病学 | 159篇 |
神经病学 | 796篇 |
特种医学 | 1909篇 |
外国民族医学 | 5篇 |
外科学 | 5731篇 |
综合类 | 2548篇 |
一般理论 | 1篇 |
预防医学 | 1067篇 |
眼科学 | 383篇 |
药学 | 1002篇 |
20篇 | |
中国医学 | 778篇 |
肿瘤学 | 928篇 |
出版年
2024年 | 36篇 |
2023年 | 450篇 |
2022年 | 662篇 |
2021年 | 1059篇 |
2020年 | 1121篇 |
2019年 | 955篇 |
2018年 | 885篇 |
2017年 | 921篇 |
2016年 | 815篇 |
2015年 | 794篇 |
2014年 | 1402篇 |
2013年 | 1447篇 |
2012年 | 1162篇 |
2011年 | 1348篇 |
2010年 | 994篇 |
2009年 | 961篇 |
2008年 | 1008篇 |
2007年 | 998篇 |
2006年 | 867篇 |
2005年 | 742篇 |
2004年 | 641篇 |
2003年 | 502篇 |
2002年 | 379篇 |
2001年 | 338篇 |
2000年 | 271篇 |
1999年 | 244篇 |
1998年 | 199篇 |
1997年 | 201篇 |
1996年 | 156篇 |
1995年 | 170篇 |
1994年 | 138篇 |
1993年 | 110篇 |
1992年 | 101篇 |
1991年 | 72篇 |
1990年 | 75篇 |
1989年 | 61篇 |
1988年 | 65篇 |
1987年 | 46篇 |
1986年 | 45篇 |
1985年 | 44篇 |
1984年 | 48篇 |
1983年 | 27篇 |
1982年 | 39篇 |
1981年 | 42篇 |
1980年 | 23篇 |
1979年 | 18篇 |
1978年 | 14篇 |
1977年 | 9篇 |
1976年 | 13篇 |
1975年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
1.
2.
《中医科学杂志(英文)》2022,9(2):166-180
ObjectiveTo observe the relationship between the different stages of type 2 diabetes mellitus (T2DM) and the intestinal flora and verify its underlying mechanism.MethodsT2DM rats were generated by high-fat diet (HFD) combined with intraperitoneal streptozotocin (STZ) injection. The rats were divided into four groups: the control group (fed with normal feed for 1 month), the HFD group (fed with HFD for 1 month), the T2DM group (HFD combined with STZ and blood glucose ≥11.1 mM), and the unformed T2DM model (Un-mod) group (HFD combined with STZ and blood glucose <11.1 mM). Feces were collected, and bacterial communities in the fecal samples were analyzed by 16S rRNA gene sequencing. The content of short-chain fatty acids (SCFAs) in feces was measured by gas chromatography. Western blot and quantitative real-time polymerase chain reaction were used to detect the expression of G protein-coupled receptor 41 (GPR41) and GPR43.ResultsAt different stages of T2DM, the intestinal flora and SCFAs content of rats were significantly decreased (all P < .05). Our results indicated that g__Prevotella had a significant negative correlation, and g__Ruminococcus_torques_group and g__lachnoclastic had a significant positive correlation with blood glucose. The content of SCFAs, in particular acetate and butyrate, in rat feces of different stages of T2DM were significantly reduced, as well as GPR41 and GPR43 expression. The results in the Un-mod group were similar to the T2DM group, and the expression of GPR41 and GPR43 proteins were significantly higher than those in the T2DM group (both P < .001).ConclusionThe intestinal flora–SCFAs–GPR41/GPR43 network may be important in the development of T2DM. Decreasing blood glucose levels by regulating the intestinal flora may become a new therapeutic strategy for T2DM, which has very important clinical and social values. 相似文献
3.
Guo-Quan Shi Huajun Zhu & Zhen-Guo Yan 《Communications In Computational Physics》2022,31(4):1215-1241
A priori subcell limiting approach is developed for high-order flux reconstruction/correction procedure via reconstruction (FR/CPR) methods on two-dimensional unstructured quadrilateral meshes. Firstly, a modified indicator based on
modal energy coefficients is proposed to detect troubled cells, where discontinuities
exist. Then, troubled cells are decomposed into nonuniform subcells and each subcell has one solution point. A second-order finite difference shock-capturing scheme
based on nonuniform nonlinear weighted (NNW) interpolation is constructed to perform the calculation on troubled cells while smooth cells are calculated by the CPR
method. Numerical investigations show that the proposed subcell limiting strategy on
unstructured quadrilateral meshes is robust in shock-capturing. 相似文献
4.
5.
Guoliang Zhang & Tao Xiong 《Communications In Computational Physics》2022,32(1):126-155
We propose a high order finite difference linear scheme combined with a
high order bound preserving maximum-principle-preserving (MPP) flux limiter to
solve the incompressible flow system. For such problem with highly oscillatory structure but not strong shocks, our approach seems to be less dissipative and much less
costly than a WENO type scheme, and has high resolution due to a Hermite reconstruction. Spurious numerical oscillations can be controlled by the weak MPP flux
limiter. Numerical tests are performed for the Vlasov-Poisson system, the 2D guiding-center model and the incompressible Euler system. The comparison between the linear
and WENO type schemes, with and without the MPP flux limiter, will demonstrate the
good performance of our proposed approach. 相似文献
6.
《Journal of cranio-maxillo-facial surgery》2022,50(9):686-691
The aim of the study was to compare automated and manually conducted (slice-by-slice) virtual orbital wall reconstruction in terms of PSI design, manufacture, and clinical application for orbital fracture management.Patients with orbital wall fractures were evaluated for the potential for treatment with PSI, based on automated virtual wall reconstruction; these formed the main group. The surgical outcomes of these main-group patients' treatments were compared with those of the control group, which comprised patients randomly selected for this study, each of whom had the same orbital trauma patterns and were also managed with PSI. However, the control group patients were treated using ‘slice-by-slice’ virtual orbital reconstruction.Mean volume differences between the intact and reconstructed orbit were 0.65 ± 0.26 cm3 in the main group (n = 23) and 0.57 ± 0.23 cm3 in the control (n = 27; p = 0.837). In both groups, no cases of implant malposition or enophthalmos were detected after surgery. Orbital shape difference was similar for the main group and the control, at ?3.3 ± 3.5% and 3.25 ± 2.5%, respectively (p = 0.929). Diplopia was diagnosed at the 3-month follow-up in 13.0% of the main group and in 11.1% of the control (p = 0.651). The average times spent on computer-aided design (CAD) procedures, including segmentation, virtual orbital reconstruction, and PSI design, were 36.7 ± 6.9 min in the main group and 72.9 ± 7.7 min in the control group (p < 0.001).Within the limitations of the study it seems that PSI based on automated virtual reconstruction is a relevant alternative treatment option for orbital fractures because of its clinical efficacy that is similar to PSI based on a ‘slice-by-slice’ CAD protocol. 相似文献
7.
8.
9.
10.
C. Vogrig J.-S. Louis F. Avila R. Gillet G. Hossu A. Blum-Moyse P.A. Gondim Teixeira 《Diagnostic and interventional imaging》2021,102(3):181-187
PurposeThe purpose of this study was to compare morphologic assessment and relaxometry of patellar hyaline cartilage between conventional sequences (fast spin-echo [FSE] T2-weighted fat-saturated and T2-mapping) and synthetic T2 short-TI inversion recovery (STIR) and T2 maps at 1.5 T magnetic resonance imaging (MRI).MethodThe MRI examinations of the knee obtained at 1.5 T in 49 consecutive patients were retrospectively studied. There were 21 men and 28 women with a mean age of 45 ± 17.7 (SD) years (range: 18–88 years). Conventional and synthetic acquisitions were performed, including T2-weighted fat-saturated and T2-mapping sequences. Two radiologists independently compared patellar cartilage T2-relaxation time on conventional T2-mapping and synthetic T2-mapping images. A third radiologist evaluated the patellar cartilage morphology on conventional and synthetic T2-weighted images. The presence of artifacts was also assessed. Interobserver agreement for quantitative variables was assessed using intraclass correlation coefficient (ICC).ResultsIn vitro, conventional and synthetic T2 maps yielded similar mean T2 values 58.5 ± 2.3 (SD) ms and 58.8 ± 2.6 (SD) ms, respectively (P = 0.414) and 6% lower than the expected experimental values (P = 0.038). Synthetic images allowed for a 15% reduction in examination time compared to conventional images. On conventional sequences, patellar chondropathy was identified in 35 patients (35/49; 71%) with a mean chondropathy grade of 4.8 ± 4.8 (SD). On synthetic images, 28 patients (28/49; 57%) were diagnosed with patellar chondropathy, with a significant 14% difference (P = 0.009) and lower chondropathy scores (3.7 ± 4.9 [SD]) compared to conventional images. Motion artifacts were more frequently observed on synthetic images (18%) than on conventional ones (6%). The interobserver agreement was excellent for both conventional and synthetic T2 maps (ICC > 0.83). Mean cartilage T2 values were significantly greater on synthetic images (36.2 ± 3.8 [SD] ms; range: 29-46 ms) relative to conventional T2 maps (31.8 ± 4.1 [SD] ms; range: 26-49 ms) (P < 0.0001).ConclusionDespite a decrease in examination duration, synthetic images convey lower diagnostic performance for chondropathy, greater prevalence of motion artifacts, and an overestimation of T2 values compared to conventional MRI sequences. 相似文献